Posted by ibrahim on .
Select a variable (mean, proportion, variance or standard deviation) of interest to you and collect data consisting of at least 30 values.
Define the variable.
Define the population.
Describe how the sample was selected.
Use Microsoft Excel (and MegaStat if at all possible) to determine the confidence interval

math please help me 
PsyDAG,
Only you can define the variable you want to measure. We do not know your interests.